DE102008046446B4 - compact drive - Google Patents

Abstract

Compact drive comprising a space area for gears, a space area for an electric motor, and a space area for an electronic circuit, wherein a pressure compensation means (50, 70) is arranged in the space area for the transmission and the space area for the transmission with the space area for the electric motor Connect pressure-equalizing, oil-tight and airtight, the pressure equalizing means (50, 70) comprising a volume-variable element, characterized in that the pressure equalizing means (50, 70) is a bellows which is attached to a cylinder (30), the cylinder ( 30) is made in one piece with a housing part (1).

Description

The invention relates to a compact drive according to the features of the preamble of claim 1.

It is known to provide an electric motor and a transmission connected in a geared motor. Geared motors and also geared motors with integrated feed circuit for the electric motor can be described as compact drives.

The DE 42 40 044 C2 relates to a pressure equalization arrangement for electric motors with closed motor housings known. An opening in a wall part between the motor housing and the gear housing is closed by a cover made of a liquid-impermeable and gas-permeable material.

The DE 90 00 324 U1 relates to a drive device for adjusting a member with a device housing having an opening to the atmosphere, which is covered by a gas-permeable membrane.

The EP 0 417 344 A1 relates to a housing with in a housing wall opening at the edge watertight held pressure compensation element in the form of a PTFE membrane.

The DE 201 19 461 U1 relates to an electric motor drive with a gear and a housing having at least one micro-aperture.

From the DE 10 2006 060 865 A1 a compact drive is known in which a membrane is arranged between two spatial areas.

The invention has for its object to improve the service life in a compact drive.

According to the invention the object is achieved in the compact drive according to the features specified in claim 1.

Features of the invention in the compact drive are that the compact drive comprises at least a transmission space, an electric motor space and an electronic circuit space,
wherein a pressure compensation means is arranged in the space area for the transmission and connect the space area for the transmission and the space area for the electric motor pressure-compensating, oil and airtight,
wherein the pressure compensation means comprises a variable volume element.

The advantage here is that the pressure difference between the space area in the transmission and the environment over the spatial range of the electric motor can be compensated and thus the service life of sealing shaft seals are improved. These include both a shaft seal, which seals to the environment, and a shaft seal, which seals to the space region of the electric motor. As a lubricating oil is thus a liquid oil usable and the spatial area of the transmission partially filled. The remaining air in the space of the transmission contributes significantly to the balanced pressure difference.

In an advantageous embodiment, the pressure compensation means is arranged in a partial region of the spatial region of the transmission, which covers at an imaginary revolution of a toothing part on the circumference of a meshing with the peripheral toothing part meshing part. The advantage here is that the housing of the compact drive is so convex executable that liquids flow well, and the increased space required is used for the pressure compensation means.

In an advantageous embodiment, the transmission comprises at least one arranged in a plane gears spur gear, wherein the pressure compensation means are arranged in the plane of the gears. The advantage here is that the additional volume of construction for the pressure compensation means at the same time causes fluids to drain well in various mounting orientations on the surface of the housing.

In an advantageous embodiment, the pressure compensation means are arranged in a plane perpendicular to the axes of the gears of the transmission plane. The advantage here is that the time required for the flow of liquids on the surface of the housing space is utilized.

In an advantageous embodiment, the electronic circuit is designed as a converter or as a soft-start electronics for the electric motor. The advantage here is that the rotational speed and the torque of the electric motor can be controlled and / or determined at least as an estimated value and thus also the power can be determined, from which a temperature determination for the spatial area of the transmission can be carried out. In this way, the volume to be compensated can be determined and issued on exceeding the compensation capacity of the pressure compensation means a warning or shutdown of the drive executable.

In an advantageous embodiment of the electronic circuit of the electric motor can be fed, wherein by means of the electric motor, the transmission The advantage here is that high output torques can be achieved and the additional construction volume for the engine and the electronic circuit for pressure equalization in the heated transmission can be used.

In an advantageous embodiment, the spatial region of the electric motor and the spatial region of the electronic circuit are connected by means of an air-permeable opening in the housing part. The advantage here is that on the one hand, a pressure equalization of the lubricating oil-containing space portion of the transmission to the air-filled space region of the electric motor is executable and on the other hand, an air pressure compensation of this space area over the spatial area of the electronic circuit to the environment is executable.

In an advantageous embodiment, the spatial region of the electronic circuit is connected to the environment via such a semipermeable membrane that the semipermeable membrane can be flowed through to equalize the pressure of air, but liquid water and / or water vapor does not pass through the semipermeable membrane. The advantage here is that no water accumulates in the engine compartment area and thus the risk of corrosion is reduced.

In an advantageous embodiment, the pressure compensation means comprise a umstülpbare membrane, in particular wherein the membrane is provided clamped between a housing part and a housing cover or between a first sleeve part received in the housing part and a second sleeve part received in the housing cover. The advantage here is that a simple manufacture of the pressure compensation means is providable that when plugging and connecting the housing cover on the housing part, the membrane only needs to be interposed and then the connection of the housing cover to the housing part is executable.

In an advantageous embodiment, the pressure compensation means comprise a cylinder movable in a piston or a bellows. The advantage here is that simple cost-effective means are sufficient.

In an advantageous embodiment, the pressure compensation means comprise a plastic container, in particular in which a Umstülpbare membrane is provided vulcanized. The advantage here is that the pressure compensation agent is vorfertigbar. It can then be used as a whole and connected to the housing part.

In an advantageous embodiment, the transmission is at least partially filled with lubricating oil and / or air. The advantage here is that the transmission is lubricated optimally with a minimum amount of lubricating oil.

In an advantageous embodiment, the output shaft of the transmission is sealed to the environment by means of a shaft seal. The advantage here is that the pressure differences are reducible and thus the service life can be increased.

In an advantageous embodiment, the volume-variable element is designed, for example, as a bellows or a piston, wherein the volume enclosed by the element is in air exchange with the space region of the electric motor or with the spatial region of the transmission that at high temperature in the spatial region of the transmission, the enclosed volume is minimal or maximum. The advantage here is that high temperature differences are made possible down or up from an initial temperature.

In an advantageous embodiment, the pressure compensation means comprise a volume-variable element whose volume is determined by the temperature of the transmission, in particular exclusively. The advantage here is that a volume proportional to the temperature is providable.

Further embodiments and advantages will become apparent from the dependent claims.

The invention will now be explained in more detail by means of exemplary embodiments with reference to the drawing. It shows purely schematically:

1 a three-dimensional oblique view of a compact drive according to the invention;

2 a section through the in 1 shown compact drive;

3 a cut like in 2 a further embodiment in an initial state;

4 a section of in 3 embodiment shown in a heated operating condition;

5 a cut like in 2 another embodiment in an initial state;

6 a section of in 5 embodiment shown in a heated state;

7 a cut like in 2 by a modified embodiment in an initial state; and

8th a section of in 7 shown embodiment in a heated state.

In the 1 is an oblique view of a partially open device according to the invention shown, which is provided as a compact drive. In the 2 an associated section is shown.

The compact drive comprises a housing part 1 , which is at least partially housing forming a space for a transmission, a space area for an electric motor and a space area for an electronic circuit. The electronic circuit feeds the electric motor that drives the transmission.

The space area of the gearbox is covered by a housing cover 22 ( 2 ), which can be screwed to the housing part. In this case, the housing cover 22 Bearing seats for the bearings 5 . 7 . 8th on. Likewise, the housing part 1 Bearing seats for the bearings 5 . 7 . 8th a rotor shaft of the electric motor, an intermediate shaft and an output shaft.

On the output shaft is the gear 4 arranged and connected to this form-fitting and / or non-positively. Next to the warehouse 5 The output shaft as well as to the space of the electric motor provided bearing the rotor shaft is a seal, such as a shaft seal 6 , intended.

As in the 2 to 8th shown, the rotor shaft protrudes with an end portion through a recess in an intermediate wall into the spatial area of the transmission. The intermediate wall separates the spatial area of the transmission and the space area of the electric motor. On the end portion of the rotor shaft, a pinion is arranged. The remaining between the motor shaft and recess opening is sealed by means of another shaft seal.

The space region of the electric motor and the spatial region of the electronic circuit are connected to one another by means of a recess, so that air can be exchanged between the spatial regions.

The spatial area of the electronic circuit is partially formed by a cover element, not shown, adjoining the area of the electric motor.

Towards the environment, a ventilation device is provided which allows an air pressure equalization between the space in the electronic circuit and the ambient air. Vorzugswiese here a semi-permeable membrane is used, which is indeed permeable to air but impermeable to water vapor.

A first membrane 2 . 20 which is air and oil-tight, is in a two-piece sleeve 3 . 25 arranged. On the first sleeve part 3 is a second sleeve part 25 placed. This is an edge region of the first membrane 2 . 20 between the first and second sleeve part 3 . 25 trapped. The second sleeve part 25 supports with a portion of a housing cover-side end face on the housing cover 22 from, so that a compound of the second sleeve part 25 and the first membrane enclosed volume is created with the space area of the transmission.

Another membrane 9 . 23 is in another two-piece sleeve 10 . 24 provided, which is arranged in a corresponding manner.

The first sleeve part 3 and the other first sleeve part 10 are fixed with a partially closed end face on the intermediate wall. A passage opening in the respective first sleeve part corresponds to a continuous recess in the intermediate wall, so that of the respective first sleeve part 3 . 10 and the membrane 2 . 20 or the other membrane 9 . 23 enclosed volume via a vent 21 is connected to the space area of the electric motor.

2 shows both states of the membranes simultaneously. Depending on the air pressure difference is the first membrane 2 in the first sleeve part 3 or in the everted state is the first membrane 20 in the second sleeve part 25 arranged. The further membrane 9 . 23 is in 2 also in the first state with reference numerals 9 and in the everted state with reference numerals 23 shown.

The sleeve parts can also be integral with the lid or the housing part 1 be made, in particular cast.

Two pods 3 . 25 ; 10 . 24 serve to increase the variable volume in the spatial area of the transmission and thus to be able to keep the pressure in the spatial area of the transmission longer constant.

The membrane and the other membrane are arranged so that the space area of the transmission relative to the space region of the electric motor is oil and airtight.

The stator 11 the electric motor is by means of elastically deformable areas 12 of the housing part 1 trapped by a screw 13 two such from the other housing part 1 projecting areas on each other.

The gearbox is designed as a spur gearbox in the compact drive. In contrast to an epicyclic gear, such as planetary gear or Zyklogetriebe run the teeth partners in a spur gear not. The pressure equalization elements require additional space enclosed by the housing. This additionally enclosed space offers the advantage that a surface of the housing is made as convex as possible. Thus, the compact drive is used for example in plants of the beverage industry or hygienic areas, because liquids run well on convex surfaces. The pressure compensation means are located in that region of space which is covered at an imaginary revolution of a toothing part on the circumference of a meshing with the peripheral toothing part meshing part. Thus, on the one hand pressure equalization for the transmission range is achieved in the additional volume of construction and on the other hand, a drainage of liquids is ensured on the surface of the housing. This is particularly important when not only lubricating oil, but also air is filled in the transmission area, since changes in temperature, the pressure in the transmission area changes significantly. Since the shaft seals only withstand a defined, known internal pressure in the housing, the tightness, or the service life of the shaft seals is improved by means of the pressure compensation means. Temperature changes affect the service life of the shaft seals only slightly.

In further embodiments of the invention, the said sleeve parts are 3 . 10 integral with the housing part 1 executed. Likewise are the sleeve parts 24 . 25 integral with the housing cover 22 executable. The molds of the two parts can be quickly and easily executed with the volume limits specified by the sleeves.

In the in the 3 to 8th the embodiments shown are the sleeves as a cylinder 30 made in one piece with a closed and an open end face. The closed end face is screwed tightly to the intermediate wall, so that an air-permeable connection, not shown, forms with the space region of the electric motor. For this purpose, the closed side and the end wall each have a corresponding opening. The open end face points towards the spatial area of the gearbox. Various separation elements separate the volume in the cylinder in two air volumes and oil-tightly separated sub-volumes, which are each connected to either the space area of the transmission or the space area of the electric motor.

In the 3 another compact drive according to the invention is shown, in which the pressure compensation means as an alternative to the above-described evertable membrane by means of a in a cylinder 30 movable piston 31 are executed. The piston separates the volume in the cylinder 30 in two air and oil-tight separate subvolumes. A partial volume is connected to the spatial area of the transmission and an intermediate wall-side partial volume with the spatial area of the electric motor. Here is the cylinder 30 by means of a screw 32 attached to the partition. The vent 21 is in 3 not visible.

In the 4 is for the embodiment after 3 another position of the piston 31 shown. This case occurs at elevated temperature in the transmission. The air in the area of the gearbox expands and pushes the piston towards the partition. The air between the piston and the partition-side partial volume in the sleeve is determined by the in 4 not shown vent 21 pressed into the space area of the electric motor. At low temperatures, the air and lubricating oil in the transmission section contracts and the piston moves to the position 3 back.

In further embodiments of the invention, the cylinder 30 with the housing part 1 made in one piece. Then the screw is eliminated 32 ,

In the 5 is as an alternative pressure compensation means a housing cover side on the cylinder 30 attached bellows 50 shown. The vent 21 to the space area of the engine is not shown.

In the 6 is the same embodiment as in 5 shown, with the bellows is extended maximum, because the temperature in the transmission area is higher than at 5 ,

In the 7 is in turn as an alternative pressure compensation means a motor side in the cylinder 30 attached bellows 70 shown, with the vent opening 21 not shown to the space area of the engine. The advantage of a bellows folded out in the relaxed state on the motor side is that it can be produced more easily, in particular using injection-molding technology.

In the 8th is the same embodiment as in 7 shown, wherein the bellows is retracted, because the temperature in the transmission area is higher than at 7 ,

The use of bellows has the advantage that the material is not bent by 180 °, as in the case of an inverted membrane. As a result, bellows offer a longer service life. A bellows also allows a continuous volume change and thus a continuous pressure equalization. As a result, there are no peak pressures over the entire compensatable pressure difference, and the risk of leaks at the shaft seals is lower.

In a further embodiment of the invention, the cylinder 30 designed as a plastic part or plastic container, in which the everting membrane or the bellows is provided molded in a multi-component injection molding. Thus, this plastic part in the housing part 1 inserted, in particular einschlagbar provided, with a tight connection to the vent 21 will be produced. The housing part is made of metal, such as steel or aluminum.

In a housing part in casting, the corresponding sleeve can also be encapsulated as a cylinder jacket surface.

The membranes or bellows are preferably made of an elastomer such as a fluororubber or nitrile rubber, especially NBR or HNBR or FKM. The sleeve or the membrane or the bellows can also be turned on or struck in order to obtain a tight connection with the corresponding elements.

Thus, the transmission is filled with lubricating oil and sealed against the environment and the space of the electric motor. A vent valve, which usually connects the space of the transmission with the environment, is not necessary. As a result, no oil foam in the environment escape and the space area of the transmission does not have to "breathe", d. H. Also does not exchange air between shaft seal and shaft with the environment. This reduces the load on the shaft seals and the contamination of the lubricating oil. As a result, the service life of the lubricating oil and the shaft seals and thus the transmission is increased.

LIST OF REFERENCE NUMBERS

1

housing part

2

first membrane (initial state)

3

first sleeve part

4

gear

5

camp

6

Shaft seal

7

Bearings of the intermediate shaft

8th

camp

9

another membrane

10

another first sleeve part

11

stator

12

elastically deformable region of the housing part 1

13

screw

20

first membrane (everted, heated state)

21

Vent opening to the area of the electric motor

22

housing cover

23

another membrane in the everted state

24

another second sleeve part

25

second sleeve part

30

cylinder

31

piston

32

screw

50

Housing side mounted bellows

70

Motor-mounted bellows

Claims (15)

Compact drive comprising a space area for transmissions, a space area for an electric motor, and a space area for an electronic circuit, wherein a pressure compensation means ( 50 . 70 ) is arranged in the space area for the transmission and connect the space area for the transmission with the space area for the electric motor pressure-compensating, oil and airtight, wherein the pressure compensation means ( 50 . 70 ) comprises a volume-variable element, characterized in that the pressure compensation means ( 50 . 70 ) is a bellows attached to a cylinder ( 30 ), wherein the cylinder ( 30 ) in one piece with a housing part ( 1 ) is executed. Compact drive according to claim 1, characterized in that the pressure compensation means ( 50 . 70 ) are arranged in that portion of the space area for the transmission, which is covered in an imaginary rotation of a toothing part on the circumference of an engaging with the toothing part, another toothing part. Compact drive according to one of the preceding claims, characterized in that the transmission comprises at least one arranged in a plane gears spur gear, said pressure equalization means ( 50 . 70 ) are arranged in the plane of the gears. Compact drive according to one of claims 2 or 3, characterized in that the pressure compensation means ( 50 . 70 ) are arranged in a plane perpendicular to the axes of the gears of the transmission. Compact drive according to one of the preceding claims, characterized in that the electronic circuit is designed as a converter or as a soft-start electronics for the electric motor. Compact drive according to one of the preceding claims, characterized in that the electric motor from the electronic circuit is fed, wherein the transmission is driven by means of the electric motor. Compact drive according to one of the preceding claims, characterized in that the spatial region of the electric motor and the spatial region of the electronic circuit are connected by means of an air-permeable opening in a housing part surrounding the spatial region of the electric motor and the spatial region of the transmission at least partially surrounding housing. Compact drive according to one of the preceding claims, characterized in that the spatial region of the electronic circuit is connected to the environment via a semi-permeable membrane, wherein the semipermeable membrane for pressure equalization of air is flowed through, however, liquid water and / or water vapor does not pass through the semipermeable membrane , Compact drive according to one of the preceding claims, characterized in that the pressure compensation means ( 50 . 70 ) comprise an evertable membrane. Compact drive according to claim 9, characterized in that the membrane is provided clamped between a housing part and a housing cover or between a housing received in the sleeve and a sleeve received in the housing cover. Compact drive according to one of the preceding claims, characterized in that the pressure compensation means ( 50 . 70 ) comprise a plastic container, in which a Umstülpbare membrane is vulcanized or molded by two-component injection molding. Compact drive according to one of the preceding claims, characterized in that the transmission is at least partially filled with lubricating oil and / or air. Compact drive according to one of the preceding claims, characterized in that the spatial region of the transmission is sealed to the environment by means of a shaft seal around an output shaft around. Compact drive according to one of the preceding claims, characterized in that a volume of the volume-variable pressure compensation means ( 50 . 70 ) is determined by the temperature of the transmission. Compact drive according to one of the preceding claims, characterized in that the bellows is made of an elastomer such as NBR, HNBR or FKM.

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